High-speed tracklaying tractor



Feb. 21, 1928. 1,660,102

' w. H. sMYTH n HIGH SPEED TRACKLAKNG TRACTOR l Filed June 4,7-1923Aulllllmm 4 FFII W\TNE55ES INVENTOR Patented Feb. 21, 1928.

TUNI-TED STA TES winnaar 11. SMYTH, Vor BERKELEY, CALIFORNIA.

v11m-1 '.11r: NT .oFF-ICE.. l

HIGH-SPEED'TRACKLAYNG TRACTOR,

Application med :une 4,

ymaintaining a constant evenly distributedy resilient tension on 'thetra'ckchain automatlcallyaresponslve to changesm surface contour;andload conditions; and to etl'ec-` tively cushion the machine underthese changing conditions and therebyy reduce wear and upkeep; and toaccomplish -these 'objects with few and simplefparts, easy to yassembleor replace. i 1 Y A typical expression of my invention that accomplishesthese objects is shownin the accompanying drawing wherein:y Y` Y Fig. 1is a side elevation of the track assembly, port-ions vvbroken away forbetter illustration. ,Y

Fig. Qis a plan view, with portions'broken away and parts 'insectioni fA track-lyingtractoris essentially a travelling cog-railway whichcarries and spikes down its own cogged-track as it progresses.

This important fact has, seemingly, not' heretofore been eiectivelyrecognized inthe construction of sel-laying-track vehicles, hencevunnecessarily severe strains have been "imposedhon parts inherentlyill-adapted to withstand them. This -is especially true ot the track,`both fin itsl upper and lower-l stretches, but vparticularly kso asregards 'the ground-contact Vload-supporting `part of the vkchain-track.

toboth types and the construction ofthese vof track `-wheels iK-K1- icsskilled in the art,*I lwillvconine my; de'-l scriptionito those parts'ofthetractor struc# The construction illustratedvin the drawingandfhereina'fter described,fconforms to vvportablecog-railway conditionsby vprovidy )section g `at its forward end is pivotedv on the pin E asalreadystated, each section be- 'ing means approprlateto itsrequirements.

. As the 'track lassembly alonedistinguishes Ythe trackelayingV typevfrom the roundwheeler form of motor vehicle, the motor 4element andVitsframework being ycommon parts being within the knowledge ofmechanture directlyfaected' by my invention. But, in what follows, itis'to be understood that the sprocketed power-wheel, with its jourV"nalfbox and rame'are intended to represent not alonea power-wheel butalso, forV the purposes fo'i this disclosure, the motor A1923.,`seriaiNo. 643,257.'

fevlemen't complete with any suitable rigid,y

flexible, or resilient connections between the power element and thetrack-assemblies.

With this understanding, AL-Al represent framework pertaininglto aself-layingtrack vehicle. It carries journal-box B, and shaft C,power-wheel D, with-its circumferential teeth `or sprockets d-d.'

`"'Upontherframacnear the opposite end Vfrom the power-wheel is a stronghingen-pin E, transverse ofthe frame lmembers A-VAl, vto which it -isattached by any suitable 'means, 4indicated in the drawing by boxese-e1inwhich thel hinge-pin is secured. On

'the 'pin'E is hinged a curved upper guide- `ra'illF, and Aalso a'curved lower guide-rail G. `The^guide-rails F, and G, extend rear-'wardlyff-rom their hinge connection towards and close to thesprocket-wheel D, like the hinge members of a caliper about to caliper'thesprocketwheel vThe guide-rails F, Vand '(r,` thus constitute. withthe sprocket-wheel `D,Yan oval substantially-continuous guide- -way. f l

Trained around `thelovaly guide-'way is an endless track-layer chain H.It is formed vot links provided with tread-shoes I I,

adapted to afford a relatively wide groundbearing support for themachine. Thelinks ofthe chain! are preferably formed of parallel members`t--tl thus constituting Van `endless -ground bearing double trackrrail, adapted 'to support the weight of the machine.l Onl the links ofthe chain 'I-I, intermediate ofits track-surface and ground-'contact-surface arek journaled antit'riction rollers J-f-J', adapted toroll vupon the guiderails V'F and `Gr,-'and coact withthe teeth of thesprocket-'wheel D. f f l The'guide-rail is divided into hinged sectionsg-gll-g las shown in Fig. 1. The

'ing successively hinged to the preceding section. Adjacent to -its rearend and seof .this spring abuts in a socket Z1., and attached -to thissocket is a transversely peroratedv boss Z2, and traversingthe boss is*ay boltM, extending between the frame memy section g, except as hasbeen and will'be later noted, and indicated in the drawing.

The guide-rail F is preferably provided,

at its rearward end, with a leaf-spring F?,

and Vsection g2 of guide-rail Gr is similarlyY rovide'd as shown at G1Fig. 1.

Connected wih the guide-rail Fat f, is

'a downwardly extending turnbuckle link O, its lower end being connectedat f1 with thesocket 33, which socket forms an abutment for the spring Lof the wheels IIL-K3. The hinge-pin f1, unlike the strutbolts .M-M, isindependent of the frame A-Al, and is thus free to respond to thevact-ion of spring L, yup to ashoulder or limiting abutment p2, on 01.The link O, is guided in a bracket N, mounted on the framework of themachine', and is preferably formed in two parts o,-01. An -adjustingscrew I), connects the two parts 0 01 of the link O, and is providedwith-.a turning boss p, and lock-nut p1. l

Secured to the frame A-'Al and lengthwise thereof is a.l dependingmud-guard, one

. on each side of the track-assembly, as shown at Q-Q1, Fig. l with alaterally stiifening frame R, for each of the mud-guards. Struts. mayconnect the frames R, for extra stiffness, such for example as bolts 7',r1, r2, extending across from inudguard tomudguard. Y

Under normal conditions of operation, the curved `ground-contact ofchain H, between the peripheries of the track-wheel pairs, KIS1, and.K4-K5, tends to flatten in conformity with the level ground surface.Such .fiattening tends to slack the chain.

This slack is, simultaneously taken up by link O, vraising thehingedguide-rail F, under resilient pressure of the spring L1.

The. axle-united pairs of.trackwheels K Kl, 2-K3, lik-K5, beingwheel-units each wheel-unit is separately spring-pressed, and respondsas a unit independently and separately conforms to changing surfacecontour. In so doing they cause the hingedV guide-rail G, tocorrespondingly conform to the ground surface undulations, through theyflexing of its sections g, g1, and g2, ontheir y hinges.' But while thetrack-chain H, conforms to the ground undulations, it is prevvented frombuckling or kinking between the peripheries of the load-bearingtrackwheels, by the antifriction rollers J, J. It willrbe observed in Fig. l that the antifriction rollers do not contact with the guide-railGr, beneath the track-wheels K-KZ-IC; thus they are relieved of load.

bearing duty. The function of the rollers 1n the ground run of the chainis only antifriction and the prevention of useful andv Adestructivechain-flexure between the pe'- as antifriction supports for the chain H,

and there being a roller for each link the stress of tensioning thechain is widely'distributed, thus reducing to negligibility the 75 dutyimposed on lthe individual roller, while keeping. the cha-in on vasmoothly curved track and uniform tension throughout. K

ByV means vof the screw 1), of link O, `the amount of resilient tensionon chain H, may beadjusted tol any desired degree.' By the co-actionoflink O, Vand the loadebearlng spring L1, the operation of theguide-rail F, andupper .run of chain H, ismadevresponsive tov thevarying necessities of .surface undulations and conditions, .in takingup yor providing tensioned slackfin vvthe ground-'run of chain H.

The leaf-springs F1., and G1, by their' smoothV and silent cushionedengagement with the antifriction rollers J, J`eliminate the customarynoisy and violent poundingV of the chain as it engages and leavesjthe s`power-wheel. Y -Being reinforced and stiffened blythe 9" ientlyconformable 'to ground contours, with 105 p the result; of maintainingt-ractive surface contact with the Vground regardless Aof'its fconstantly changing contour. And the loadbearing wheels` are alwaystraveling upon a track of maximum smoothness bythe brid no,

ing of the gap between the peripheries oft e load-bearing .wheels by thehinged sections of guide-rail G., These constructions ,and

provisions thus' unify in one structure elements adapted to permit ofhigh speed with Vminimum Wear, upkeep expense, friction losses andpowerjwastage, which isthe main ob]l ect of this invention. l f

I do not desire to be limited to the particular expressions of myinventionv used 1,20

herein for illustrative purposes, nor to be limited in any other waythan inl accord with a liberal rinterpretation and the' rea-V sonablepurport of the claims. which follow and I claims'V ,p l l. A vehiclecomprising a frame, an endless chain-track with antifriction ,guide-vrollers journaled thereon intermediate of its track-surface and.ground-contact-surface adapted to constitute therewith a roller- 3guideway, a plurality of Wheel-units travelable upon the track each unitbeing curvilinearly movable independently of each other t and aseparately pivoted member on which each Wheel-unit is mounted. Y

2. A vehicle comprising a frame, an endless chaiirtrack Withantifriction guiderollers journaled thereon intermediate of itstrack-surface and ground-contact-surface adapted to constitutetherewithV a rollerguideway a plurality of curvilinearly movablespring-pressed frame-support wheelunits travelable upon thetrack-rail-surface and a separately pivoted member on which eachWheel-unit axle is journaled.

3. A vehicle comprising a frame, an endless chain-track Withantifriction guiderollers journaled thereon intermediate of itstrack-surface and ground-contact-surface adapted to constitute therewitha roller-V guideway, a plurality of concentric pairs of curvilinearlymovable support-Wheels travelable upon the track-rail-surface and aseparately pivoted member on which each Wheel pair is journal-ed.

et. In a tractor an end1ess-chain track adapted to ground support, anadjust-able support for the upper run intermediate of its end bights,and means actuated by the ground run ofthe chain adapted to raise andlower the upper run chain support.

5. In a tract-or an endless-chain track adapted to ground support, anadjustable guide rail for the upper run of the track, a support Wheeltravelable upon the ground run of the chain track, and means actuated bythe vertical movement of the Wheel adapted to raise and lower the guiderail.

6. In a tractor an endless-chain track adapted to ground support, anadjustable rail for the upper run of the track, a Wheel travelable uponthe ground run, and a spring actuated by the' vertical movement of theWheel abutting on the ground run and on the rail.

y7. In a tractor a frame and endless-chain track adapted to groundsupport, a guiderail contacting With the ground run of the chain trackthe -rail being formed of sections hinged together, and support Wheelstravelable upon the track journaled on the sections.

8. In a tractor a frame, an endless-chain track adapted to groundsupport, a. rail contacting with the ground run of the track the railbeing formed of sections hinged together, a pair of support wheelsjournaled onfand transversely or the sections adjacent to each hinge,and a spring for each Wheel pair to independently oppose its upwardmovement. j i

9. In a tractor an endless-chain track adapted to .ground support,hinged sections .forming aguide-rail paralleling its ground run, supportWheels travelable upon the chain track journaled on the hinged sections,and antifrictionrollers journaled on the chain-track co-acting With theguide-rail V*to limit the leXure of the ground run of the track.

10. In a tractor an endless-chain track adapted to ground support,hinged sections -forming a guide rail paralleling its ground run, aspring opposed track Wheel journaled on each of the sections, andantifriction WILLIAM H. sMYTH.

